VSC, ABS ,Brake & (!) lights

Connecting a battery charger (smart AGM compatible type) when working on the car is listed in the service manual. Short periods no problem, dome light shouldn't discharge the battery much. Prolonged periods w/ door open and having to go to ACC and/or IG-ON mode, will discharge the 12V causing error codes and weirdness.

A regular 12V battery charger will turn off prematurely thinking the AGM battery is fully charged, when it is actually not. If you only have a regular 12V charger, this would be better than nothing. Still best to get a smart AGM compatible 12V charger; more and more cars seem to be equiped w/ AGM batteries these days.

 

Assuming ITBland counted the blinks right in the video, there's one code (the 47 on the ECB light) that I could find. The ABS 42 and VSC 45, I did not find (in the 2006 manual copy that's been making the rounds, anyway.)

47 on the ECB would correspond to a full DTC of C1247 and have to do with the stroke sensor on the brake pedal. There are nine different INF codes that can go with that code, and there's no way to get those with light blinks, only over the diagnostic bus. So, if it's possible to get Techstream set up, that would be worth doing, both to get the INF codes for that one, and to find out what full DTCs the ABS and VSC were reporting. That would help with fixing this car, and would also let us look at what the manual says the blink codes ought to be for those codes, and why I couldn't find the ones ITBland counted. An occasional typo in the manual isn't unheard of; I did find one in my 2001 edition.

-Chap

 

Autoparts store and bluetooth OBD2 readers can NOT read all the Prius codes. (I do have an earlier BAFX reader too, and it is superior compared to the crap Elm for reasons BAFX states; the Elm was a few dollars and I dissected to see for myself.) For a few dollars more, OP can achieve dealer capabilities. ALSO, he will be able to bleed the brakes! NO bluetooth OBD2 reader will give you that capability. There are other pretty cool functions in Techstream that bluetooth OBD2 readers can NOT perform b/c these devices are severely limited.

Also, getting codes read at the dealer is likely $100 MINIMUM. Hacked mini VCI & Techstream, say $30. Junker laptop, free-$75. For $105 maximum, OP will be able to read ALL codes, ALL DAY LONG! Why not make this one time purchase in such a useful tool? If he stays w/ Toyota/Lexus, he can continue to use this Techstream laptop. If he gets rid of the Prius, and goes to a different vehicle manufacture, he can always sell his Techstream setup, recovering some to all of his initial investment. Its a win-win situation in my book, no matter how you look at it.

Yes, Antivirus software will say the hacked copy of Techstream is bad. Thus the recommendation to use on a spare junker laptop that will only be used for the Prius. There are some people who use it on their everyday laptop w/ no issues; still not recommended, but their choice.

Think of Techstream as the 1/4in impact driver, an indispensable tool if you have ever done work on a house or needed to drive screws. A traditional drill could be used to drive screws, but you'll strip a lot of heads and make life miserable, when all you have to reach for is the impact driver.

 

I'm not sure it's in principle impossible for an ELM-based scan tool to do a lot more of the stuff. ELM327 chips can do a lot (but it's worth keeping in mind that Elm sells them for $20ish a chip, so any time you buy a whole "ELM"-based dongle for half that, you know it ain't got an ELM chip, but a "compatible". Of the compatibles, the chips made by STN seem to be respectable.)

The ELM chip can handle, AFAIK, all of the comm bus protocols used in a Prius, and all of the ones you need in a J2534 dongle to use with Techstream. The J2534 dongles also do a few extra tricks, like being able to put controlled voltages or pulses on certain other pins of the connector. (Those various weird chicken-dance procedures in the manual for when you don't have Techstream, like "put a jumper in the Ts terminal and touch it to ground 8 times"? Surprise, could be that's exactly what Techstream is telling the dongle to do for those operations, not just sending some bus message.) If I'm not mistaken, some of the ELM chips actually have pins that can be used for that, and commands for setting the voltages on those pins. It's possible that some of the ELM-based dongles out there actually complete the wiring from those chip pins to pins of the OBD connector, so with the right software driver, those operations would be possible. (Check me on that; I haven't studied the datasheet in a while.)

I mentioned a while back to somebody else that J2534 turns out to be a standard for a software API, not for specific hardware. It's of a fairly manageable size, not a large bunch of functions to have to write. It would be an interesting project (for somebody with enough free time) to take one of the better ELM-based dongles and just write a J2534 driver around it. Implement the functions the dongle is capable of, write the others to throw not-supported errors, and then use that dongle and that driver on a laptop with Techstream and see how much of Techstream works and what bits don't.

I just think nobody (that I know of) has stepped up to try that, and I don't foresee my own free time becoming adequate, as interesting a project as it might be.

-Chap

 

Or, look at the electronics "hacker" community: Car Hacking 101: Tools of the Trade

 

DOH! remembered I have a Bentley manual for Gen 2!

1. 42 (1242) is Open circuit in IG2 circuit - Look at ABS relay 1, ABS relay 2, harness & connector, Skid control power supply, brake control power supply, Hybrid control system.
   (My 2011 manual adds: These codes may be also be stored if the auxiliary battery voltage drops below 9.5 V.)
2. 45 (1245) is malfunction in deceleration sensor, look at Yaw rate sensor, Zero point calibration not done, Skid control ECU.
   (My 2011 manual says to clear the codes, drive 25 mph for at least a minute and if they (42 and/or 45) come back to: REPLACE BRAKE BOOSTER WITH MASTER CYLINDER. Their caps, not mine.)
3. 47 (1247) is malfunction in stroke sensor, look at: brake pedal stroke sensor, skid control ECU, harness & connector.
   (2011 manual has the following: )

1. CHECK BRAKE PEDAL
(a) Check that the brake pedal and the brake pedal stroke sensor are properly installed and that the pedal can be operated normally.
(b) Check and adjust the brake pedal height.
(c) Adjust the brake pedal stroke sensor.
NEXT -- Continue to next step.

2. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BRAKE PEDAL STROKE SENSOR)
(a) Make sure that there is no looseness at the locking part and the connecting part of the connectors.
(b) Disconnect the skid control ECU connector and the brake pedal stroke sensor connector.
(c) Check both the connector case and the terminal for deformation and corrosion.
OK: No deformation or corrosion.
(d) Measure the resistance according to the value(s) in the table below.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

3. INSPECT SKID CONTROL ECU (SENSOR OUTPUT)
(a) Reconnect the skid control ECU connector.
(b) Turn the power switch on (IG).
(c) Measure the voltage according to the value(s) in the table below.
(measure Pin 1-3, >4.84v and <5.16v)
NG -- REPLACE BRAKE BOOSTER WITH MASTER CYLINDER
OK -- REPLACE BRAKE PEDAL STROKE SENSOR

NOTE: There are subcodes that Techstream could show you to get more specific information about the problems detected! I use AllDataDIY for my 2011, not as good as TIS, but very helpful.